Don't forget that Hero will be getting Android 2.0 soon as well.
The main difference with the droid is the keyboard (although its a grid type - not offset like a normal qwerty) and the larger screen.
Droid runs vanilla (standard) Android - so none of the fancy HTC sense touches - it resembles the user interface of the G1 and Magic.
The X10 will, like Hero, run a proprietary skin over Android - early vids mean it looks fabulous - more like a pc in operation/animation. I would wait to see how processor powers it - the X1 and X2 could be a bit laggy due to the Experia skin on those (Hero by comparison to X1 and X2 is very fast).
Have a google for some reviews - I like phandroid and phonedog - and see what appeals to you.
Factor in Cost of Contract for phones - after all if your on a cheap contract cause of the phone you have chosen then the money you save can be put aside to buy a sim free upgrade after 8 months if you like.
I went for an N97 because of the keyboard - but hated the interface so ended up buying a sim free Hero - and very pleased with it - hardly put it down and using it more to browse web + this forum than my PC with 26" monitor
